a) Field of the Invention
The invention relates to a device for generating an artificial constriction in the gastrointestinal tract with a band, which can be placed annularly about a particular portion of the gastrointestinal tract, and a closure device for connecting the end regions of the band placed annularly about the portion of the gastrointestinal tract, which, in the closed state of the closure device, encompasses a throughlet opening, the band having a hollow chamber fillable with a filling medium and extending at least over a large portion of the length of the band and, upon the filling of the hollow chamber, a wall of the band delimiting the throughlet opening extends in the direction toward the axis of the throughlet opening and decreasing the throughlet opening, and the device further comprising a foamed material body connected with the band.
b) Description of Related Prior Art
A device for generating an artificial constriction in the gastrointestinal tract is disclosed for example in EP 0 702 529 B1 in the form of a gastric band. This device comprises a band, which can be placed about the gastric inlet, developed with a longitudinally extending interior hollow chamber. To close this band placed annularly about the gastric inlet, it comprises a closure device with a first closure part disposed at one end of the band having an insertion opening, and a second closure part disposed at the other end of the band, which can be introduced through the insertion opening and which is latchable with respect to it. To constrict the passageway cross section of the throughlet opening of the band, and consequently of the gastric inlet, the hollow chamber of the band is filled with a filling medium, the quantity of the filling medium depending on the desired passageway cross section. To fill the band with the filling medium, an injection port, connected with the band is provided, which is implanted under the skin of the patient.
Apart from the development as a stomach band, a device of this type can in particular also be developed as an anal band for the closure of an, optionally, artificial anus.
A device of the above described type is disclosed in U.S. Pat. No. 6,511,490 B2. The device comprises a foamed material body encompassing the throughlet opening with a rough surface, which, for example, is an open cell polyurethane or silicone foam. This is said to prevent the device, placed about the stomach, from sliding. The foamed material body is disposed on the side face of the fillable band facing the throughlet opening.
U.S. Pat. No. 4,592,339 discloses a gastric band, which includes a multilayered band segment. Over a portion of the longitudinal extent of the band segment an inflatable balloon is disposed between the layers of this band segment, with which the size of the throughlet opening of the gastric band can be reduced.
A further gastric band is disclosed in WO 03/020183 A1. The throughlet opening of this gastric band can be varied in particular by means of a motor-driven setting unit, which cooperates with an end segment of the band. The band is encompassed by a layer of a viscoelastic material in order to protect the wall of the stomach. The viscoelastic material can comprise a foamed material.
One problem entailed in such devices for generating an artificial constriction in the gastrointestinal tract, which comprises a band with a fillable hollow chamber, is that these, sooner or later in the course of their use, can leak, such that their function is no longer ensured. Consequently, surgical removal and replacement of this band is required, which is tied to a corresponding strain on the patient. Such leaks in practice occur especially in the diaphragm delimiting the band toward the throughlet opening. Such leaks can occur for example due to material fatigue in the course of use or due to an overfilling of the band. For so-called “early” leaks, which occur up to approximately one year after the insertion of the band, most often injuries are responsible, which have occurred through a surgical instrument during the surgical, in particular laparoscopic, placement of the band.